3 lemon trees started from seed

I planted these three from seed all at the same time 2 or 3 years ago. One of them is getting very tall, but is too spindly to stay upright on its own. What can I do to correct this? The other two are much smaller, which I find odd because all of them have been kept together in the same location. Is this unusual? When I planted them I used regular bagged (purchased) garden soil mixed with some of the dirt from my compost pile. The yellow marks on the leaves are from putting them outside last summer in a plastic greenhouse. The door flap was left open but I think the reflection of the sun on the plastic burned the leaves. I know very little about growing trees and tried this as an experiment, but now I don't know what I should do to properly care for them. Any tips or advice would be much appreciated.

As you are new to this you may not be aware that it may take many years before a seedling matures and begins to flower and produce fruit. If you are serious about growing citrus, I think you would be better off to propagate using mature cuttings or to purchase a small potted specimen of the cultivar of your choosing. Having said that, were your trees the result of a single seed or multiple seeds? Which variety of lemon did the seed come from?

I do know it takes time and I'm okay with that. I tried this because my daughter loves lemons and I thought this would be fun. My concern is that the big one keeps growing and growing but it's too thin to stand up on its own. The smaller ones I'm just wondering what I should do to keep them healthy. This started as a fun experiment, but now that they're still growing I'd like to keep them going. I'm not sure what kind they are. They're just whatever is the most common type sold in a grocery store. I bought an organic lemon and uses 4 seeds from that. They all grew. The 4th plant was given to a friend and it's currently about the same size as the smallest of my 3.

I'm gonna bet that Lauri is just having some fun and was surprised that they've lasted this long. I grew a lemon from grocery store fruit seed in a pot inside my north facing narrow street on the lowest floor of a Boston brownstone. No direct light ever. Harsh winters with windows frozen shut, frost burn on the leaves where they touched window panes. I did have one flower which pleased me enormously. I knew nothing of growing citrus at that time, but I recall no more than 40 leaves when it blossomed. Of course it didn't set fruit. But I planted that 3 ft tall tree in my backyard in Florida just a couple of years later and it fruited heavily for several years. Shaded out by native hardwoods eventually.

Lauri, I'd probably cut the tall one, take off the top third to half. Somewhere above at least one branch. It's unwieldy for you now, but with a little more lateral growth, it may look better and fuller. It may take a while for new growth to start though. It's unlikely that you would kill it.

Growing citrus from grocery fruit is fun, but citrus is a lot harder to grow well than a philodendron. Soil, fertilizer, light, heat, humidity, and the species and cultivars can be pretty picky about the region they call home. You can't grow key limes well in Arizona, or blood oranges in Florida for instance. Maybe in the right sort of greenhouse or the occasional courtyard, but they just don't do well if the micronutrients are off or the humidity is not right.

There's a ton of information on this site and other sites that are specific about citrus growing if you are interested.

A store-bought lemon is likely to be either of the Eureka or Lisbon variety. Some variability in seedlings can be expected as a portion of seed produced by these varieties is by means of fertilization. I would hazard to guess three of the four seeds were produced parthenocarpically and the fourth through fertilization.

I would remove a large portion of the lanky seedling with the aim of producing a tree with a standard form. With that in mind I would prune at a point below the lowest branch and hope that new growth will result in a more or less balanced manner around the main stem. Any undesired growth can then be pinched or rubbed away in order to shape the tree. I would consider moving the tree into a smaller container - one that is slightly larger than the rootball.

Citrus trees prefer a porous medium. I suggest using a standard indoor potting soil as a base, then amending it with medium-sized bark chips, perlite and/or calcined clay. A water-soluble fertilizer with a 5-1-3 NPK ratio would be appropriate; make sure it includes micronutrients in its formulation.

Thank you for the responses. I did cut the big one by taking off the top third. It pained me to do so! A later response from Junglekeeper suggests cutting off much more, but I'll have to wait until I'm feeling brave enough for that. And it is correct that I started these on a whim, and now here we are. I'll have to spend some time reading up more info on this site. Seems there's a a lot to be learned from a good group of helpful people. I think the first order of business is to look up parthenocarpically...

Actually two of them had supports. One was the stake and the tall one had a loose piece of twine helping it stay upright. I didn't think they would stand on their own. I've removed both supports and they're doing better than I thought they would. The bigger one didn't stay up at all before but since cutting off the top it's not so bad. Thanks for the tip.